Laser printers and certain photocopiers employ cartridges that contain a supply of xerographic toner powder. These cartridges must be replaced from time to time as the toner is exhausted. Toner cartridges are relatively complex pieces of equipment, which include a hopper for holding the toner, a stirring mechanism to ensure that the toner is freely and uniformly distributed within the bin, feeding and metering devices for distributing toner in required amounts from the bin, and various equipment for transferring toner to a magnetic roller assembly.
The toner material is a fine, black powder which must be sealed within the hopper portion of the toner cartridge in order to prevent leakage during shipment, storage, and installation. Because most toner bins have an elongate slot at a lower portion thereof through which toner is metered during the use of the cartridge, manufacturers of cartridges generally insert container seals in place during the manufacturing process prior to filling the hoppers with toner. The manufacturer's seals may vary depending on the particular configuration of the cartridge; however, the seals generally comprise a barrier placed along the slot which can be removed by sliding away from the slot before the cartridge is inserted in the xerographic device.
Printer and copier cartridges are designed by the manufacturer to be discarded and replaced after the toner supply is used up. Because toner cartridges are relatively complex, expensive devices which actually have a useful life far in excess of the initial supply of toner, efforts have been made to refurbish and reuse cartridges for various copying and printing devices. A problem that is inevitably encountered in the refurbishing of these cartridges is the resealing of the exit port or slot of the hopper. Refurbishers of cartridges have devised various methods of providing a barrier or seal for the slots, generally mimicking a replacement for the original seal installed by the manufacturer. For example, Paull, U.S. Pat. No. 5,080,745, discloses a method of inserting an adhesive sheet into the slot opening of certain Canon cartridges.
To date, however, no satisfactory sealing technique has been developed for enabling reuse of cartridges for IBM laser printers, particularly IBM Toner Cartridge Model Numbers 4019 and 4029. The seal and method of the invention provide a suitable method for sealing the bin of an IBM laser printer cartridge hopper enabling refilling and reuse of the cartridge. While the seal of the invention is particularly useful for enabling reuse of the original cartridge, the seal provides a highly effective method of preventing leakage of toner and can be used for the original design of the hopper. In addition, the seal of the invention may be used on any toner hopper having an elongate discharge slot and an internal rotating mechanism such as a stirrer.
Accordingly, it is an object of the invention to provide a method of sealing a toner bin cartridge enabling refill and reuse of the cartridge. It is another object of the invention to provide an adhesive seal applied to the internal portion of the discharge slot of the toner bin, with removal of the seal occurring automatically upon initiation of use of the cartridge, with removal being affected by the existing moving parts of the cartridge. These and other objects of the invention are accomplished by means of the particular seal of the invention, a specific embodiment of which is described herein.